1. Field of the Invention
The present invention relates generally to a system that may be used to mount mass storage devices for use in a mass storage system (e.g., a network mass storage system), and more specifically, to such a mounting system wherein the mass storage devices mounted in the mounting system may comprise disk mass storage devices that have two different form factors.
2. Brief Description of Related Prior Art
Network computer systems generally include a plurality of geographically separated or distributed computer nodes that are configured to communicate with each other via, and are interconnected by, one or more network communications media. One conventional type of network computer system includes a network storage subsystem that is configured to provide a centralized location in the network at which to store, and from which to retrieve data. Advantageously, by using such a storage subsystem in the network, many of the network""s data storage management and control functions may be centralized at the subsystem, instead of being distributed among the network nodes.
One type of conventional network storage subsystem, manufactured and sold by the Assignee of the subject application (hereinafter xe2x80x9cAssigneexe2x80x9d) under the tradename Symmetrix(trademark) (hereinafter referred to as the xe2x80x9cAssignee""s conventional storage systemxe2x80x9d), includes a plurality of disk mass storage devices (e.g., disk drives) configured as one or more redundant arrays of independent (or inexpensive) disks (RAID). The disk devices are controlled by disk controllers (commonly referred to as xe2x80x9cback endxe2x80x9d controllers/directors) that are coupled via a bus system to a shared cache memory resource in the subsystem. The cache memory resource is also coupled via the bus system to a plurality of host controllers (commonly referred to as xe2x80x9cfront endxe2x80x9d controllers/directors). The disk controllers are coupled to respective disk adapters that, among other things, interface the disk controllers to the disk devices. Similarly, the host controllers are coupled to respective host channel adapters that, among other things, interface the host controllers via channel input/output (I/O) ports to the network communications channels (e.g., SCSI, Enterprise Systems Connection (ESCON), or Fibre Channel (FC) based communications channels) that couple the storage subsystem to computer nodes in the computer network external to the subsystem (commonly termed xe2x80x9chostxe2x80x9d computer nodes or xe2x80x9chostsxe2x80x9d).
In the Assignee""s conventional storage system, the disk devices are placed in respective housings and stored in one or more chassis. The chassis includes a multiplicity of sets of slots for receiving respective housings within which the respective disk devices are placed. The chassis also includes an electrical back plane having a multiplicity of electromechanical connectors. The connectors may be mated with respective electromechanical connectors of the housings to electrically and mechanically couple the disk devices to the chassis, and thereby, mount the disk devices in the chassis.
In general, two types of commercially available disk devices may be mounted in the chassis used in the Assignee""s conventional storage system: xe2x80x9clow profilexe2x80x9d and xe2x80x9chalf-highxe2x80x9d form factor disk devices. With the exception of their respective heights, a low profile form factor disk device (hereinafter xe2x80x9cLP devicexe2x80x9d) may have identically the same dimensions as a half-high form factor disk device (hereinafter xe2x80x9cHH devicexe2x80x9d). An LP device may have a height of 1 inch; an LP device may have a height of 1.6 inches.
At present, the storage capacity of an HH device may be approximately twice that of an LP device. However, the speed with which data may be read from or written to an HH device may be slower than the speed with which data may be read from or written to an LP device.
Only two types of chassis may be used in the Assignee""s conventional storage system. One type of chassis is configured to receive and mount only LP devices, and the other type of chassis is configured to receive and mount only HH devices. Thus, in the Assignee""s conventional storage system, a single chassis cannot contemporaneously receive and store both LP and HH devices; instead, all of the disk devices stored in a single chassis in the Assignee""s conventional storage system must have a single form factor (i.e., LP or HH).
This is unfortunate, since, given the above-described relative differences in the capabilities of HH and LP devices, in certain practical applications of a data storage system, it may be desirable to store in an individual chassis combinations of both HH and LP devices that, when taken together, may permit the overall performance of the system to be improved. Also unfortunately, since an individual chassis used in the Assignee""s conventional data storage system is unable to receive and store disk devices having multiple different form factors, this inherently reduces the design flexibility of the data storage system. Thus, it would be desirable to provide a mass storage device mounting system that may utilize a single type of chassis that is able to contemporaneously receive and store disk mass storage devices that have different form factors (e.g., receive and store different configurations/combinations of both HH and LP devices).
Accordingly, in broad concept, a mass storage device mounting system is provided that overcomes these and other disadvantages and drawbacks of the prior art. In one embodiment of the mounting system of the present invention, each of the mass storage devices that may be received and stored in the mounting system may comprise a respective housing or carrier device that is attached to, and at least partially encloses, a respective disk storage device (e.g., a disk drive). Each disk storage device may have a respective form factor, which form factor may be a respective one of two different possible form factors (e.g., either HH or LP).
At least one chassis may be included in the mounting system of this embodiment. The chassis may include a plurality of sets of tracks that are configured so as to be able to receive and engage the mass storage devices. The tracks may be disposed in a space defined by the chassis for receiving and storing the mass storage devices.
The chassis may also include an electrical back plane. The back plane may include a multiplicity of connectors that may be used to mount the mass storage devices in and to the chassis. Each of the connectors may be associated with a respective set of tracks in the chassis.
The tracks and the connectors may be configured such that (e.g., constructed and dimensioned), when one set of tracks receives and engages one of the mass storage devices, the mass storage device being engaged by that set of tracks may be slid along and guided by the set of tracks into mounting connection with a connector with which the set of tracks is associated.
The mass storage devices may be grouped into respective subsets, and the space defined by the chassis may include a plurality of equally sized regions. All of the disk devices in each respective subset of mass storage devices may have the same respective form factor. The tracks and the connectors may also be configured so as to permit one or more of the respective subsets of the mass storage devices to be mounted in one or more respective equally sized regions.
If the form factor of the disk devices in a given subset of mass storage devices is a certain one (e.g., HH) of the two possible form factors of the disk devices, then at most two respective mass storage devices may be comprised in the given subset. Conversely, if the form factor of the disk devices in the given subset of mass storage devices is the other (e.g., LP) of the two possible form factors of the disk devices, then at most three respective mass storage devices may be comprised in the given subset of mass storage devices.
Each respective carrier device may include two respective mutually oppositely facing surfaces. Members or projections may extend or project from these surfaces and may be inserted into and engaged by certain sets of tracks. Also in this embodiment, the number of connectors may be equal to M, and the maximum number of mass storage devices that may be mounted in the chassis may be equal to N, with M being greater than N.
The mounting system may include a plurality of chassis. The tracks may be formed in one or more sets of associated racks comprised in each of the chassis. Each set of associated racks may define two respective equally sized regions.
Thus, the mass storage device mounting system of the present invention may utilize a single type of chassis that is able to receive and store combinations of disk mass storage devices that have two different respective form factors (e.g., receive and store combinations of both HH and LP devices). Advantageously, by appropriately selecting the respective combinations of disk devices to be stored in the chassis, the overall performance of a data storage system that comprises the mounting system of the present invention may be improved compared to the prior art. Also advantageously, since a chassis used in the mounting system of the present invention is able to receive and store disk devices having multiple different form factors, this inherently improves the design flexibility of a data storage system that comprises the mounting system of the present invention compared to the prior art.